code: def pick_channels_regexp(ch_names, regexp):
      """Pick channels using regular expression.
  
      Returns the indices of the good channels in ch_names.
  
      Parameters
      ----------
      ch_names : list of str
          List of channels.
  
      regexp : str
          The regular expression. See python standard module for regular
          expressions.
  
      Returns
      -------
      sel : array of int
          Indices of good channels.
  
      See Also
      --------
      pick_channels
  
      Examples
      --------
      >>> pick_channels_regexp(['MEG 2331', 'MEG 2332', 'MEG 2333'], 'MEG ...1')
      [0]
      >>> pick_channels_regexp(['MEG 2331', 'MEG 2332', 'MEG 2333'], 'MEG *')
      [0, 1, 2]
      """
      r = re.compile(regexp)
      return [k for k, name in enumerate(ch_names) if r.match(name)]
  
imports: import re
  from copy import deepcopy
  import numpy
  from ..utils import _check_option, _ensure_int, _validate_type, fill_doc, logger, verbose, warn
  from .constants import FIFF
label_desc: Use image node_id 4 for calling a global function with example usage: pick_channels_regexp(ch_names, regexp) and returns: unknown